Step Evolution and Growth Rate on {101} Faces of Potassium Dihydrogen Phosphate Crystals Grown at High Supersaturation

Abstract

AbstractThe surface micromorphology of the {101} faces of potassium dihydrogen phosphate (KDP) crystals grown at different supersaturation conditions is systematically compared using atomic force microscopy. The height and width of the crystals during different growth steps are measured. The pyramidal face growth rate of KDP crystals is tested by a laser polarization interference system. The X‐ray rocking curve is used to measure the structural perfection of the {101} face of the KDP crystals. The results show that the growth rate of the {101} face increases with the supersaturation degree, and the rate is faster than that of the {100} face at a low supersaturation degree. Step bunching first increases and then decreases upon increasing the supersaturation, and the step height reaches a maximum value of about 6.0–6.9 nm at σ = 0.08 and 0.09. The crystal structural perfection is the worst under these conditions. It should be noted that 2D nuclei form on the surface terraces when the supersaturation is about 0.07. Dendrite‐like steps may be formed due to the development of these 2D nuclei. This work provides a reference for further researching the step evolution law of other crystalline materials.